#!/usr/bin/env zsh
# Cut a clip from a video

setopt LOCAL_OPTIONS ERR_RETURN NO_UNSET PIPE_FAIL

zmodload zsh/zutil
local -a o_help=()
local -a o_from=()
local -a o_to=()
local -a o_vencoder=()
local -a o_aencoder=()
local -a o_hardcode_subs=()
zparseopts -D -K -- h=o_help -help=o_help -from:=o_from -to:=o_to \
           -vencoder:=o_vencoder -aencoder:=o_aencoder \
           -hardcode-subs=o_hardcode_subs
if [[ ${#o_help} -ne 0 || ! -v 2 || ${#o_from} -ne 2 || ${#o_to} -ne 2 ]]; then
    local ret=$(( ${#o_help} ^ 1 ))
    print -u $(( 1 + ${ret} )) "usage: ${0} [-h|--help]" \
          "--from <HH:MM:SS.MMM> --to <HH:MM:SS.MMM>" \
          "[--vencoder <ENCODER>] [--aencoder <ENCODER>] [--hardcode-subs]" \
          "<INPUT FILE> <OUTPUT FILE> [FFMPEG OPTIONS]"
    print "\e[3mYou can set bitrates with -b:v and -b:a in FFMPEG OPTIONS." \
        "The -vn / -an / -sn / -dn options can be used to skip inclusion of" \
        "video, audio, subtitle and data streams respectively."
    print "Visit <https://trac.ffmpeg.org/wiki#Encoding> for tips\e[0m"
    return ${ret}
fi

local input=${1}
shift
local output=${1}
shift
local ffmpeg_options=(${@})
local from=${o_from[2]}
local to=${o_to[2]}
local vencoder="copy"
local aencoder="copy"
[[ ${#o_vencoder} -eq 2 ]] && vencoder=${o_vencoder[2]}
[[ ${#o_aencoder} -eq 2 ]] && aencoder=${o_aencoder[2]}
local subtitle_options=(-codec:s copy)
local compat_options=(-pix_fmt yuv420p) # Android doesn't like yuv420p10le

if [[ ${#o_hardcode_subs} -ne 0 ]]; then
    local tmpass=$(mktemp --suffix='.cutvid.ass')
    ffmpeg -i ${input} -y ${tmpass}
    subtitle_options=(-sn -vf ass=${tmpass} )
fi

ffmpeg -i ${input} \
       -ss ${from} -to ${to} \
       -codec:v ${vencoder} -codec:a ${aencoder} ${subtitle_options} \
       ${compat_options} ${ffmpeg_options} ${output}

[[ ${#o_hardcode_subs} -ne 0 ]] && rm --verbose ${tmpass}